soc-dmaengine-pcm.c

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/*
 *  Copyright (C) 2012, Analog Devices Inc.
 *  Author: Lars-Peter Clausen <[email protected]>
 *
 *  Based on:
 *  imx-pcm-dma-mx2.c, Copyright 2009 Sascha Hauer <[email protected]>
 *  mxs-pcm.c, Copyright (C) 2011 Freescale Semiconductor, Inc.
 *  ep93xx-pcm.c, Copyright (C) 2006 Lennert Buytenhek <[email protected]>
 *            Copyright (C) 2006 Applied Data Systems
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under  the terms of the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/dmaengine.h>
#include <linux/slab.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <sound/dmaengine_pcm.h>

struct dmaengine_pcm_runtime_data {
    struct dma_chan *dma_chan;
    dma_cookie_t cookie;

    unsigned int pos;

    void *data;
};

static inline struct dmaengine_pcm_runtime_data *substream_to_prtd(
    const struct snd_pcm_substream *substream)
{
    return substream->runtime->private_data;
}

void snd_dmaengine_pcm_set_data(struct snd_pcm_substream *substream, void *data)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

    prtd->data = data;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_data);

void *snd_dmaengine_pcm_get_data(struct snd_pcm_substream *substream)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

    return prtd->data;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_data);

struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

    return prtd->dma_chan;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_get_chan);

int snd_hwparams_to_dma_slave_config(const struct snd_pcm_substream *substream,
    const struct snd_pcm_hw_params *params,
    struct dma_slave_config *slave_config)
{
    enum dma_slave_buswidth buswidth;

    switch (params_format(params)) {
    case SNDRV_PCM_FORMAT_S8:
        buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
        break;
    case SNDRV_PCM_FORMAT_S16_LE:
        buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
        break;
    case SNDRV_PCM_FORMAT_S18_3LE:
    case SNDRV_PCM_FORMAT_S20_3LE:
    case SNDRV_PCM_FORMAT_S24_LE:
    case SNDRV_PCM_FORMAT_S32_LE:
        buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES;
        break;
    default:
        return -EINVAL;
    }

    if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
        slave_config->direction = DMA_MEM_TO_DEV;
        slave_config->dst_addr_width = buswidth;
    } else {
        slave_config->direction = DMA_DEV_TO_MEM;
        slave_config->src_addr_width = buswidth;
    }

    return 0;
}
EXPORT_SYMBOL_GPL(snd_hwparams_to_dma_slave_config);

static void dmaengine_pcm_dma_complete(void *arg)
{
    struct snd_pcm_substream *substream = arg;
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

    prtd->pos += snd_pcm_lib_period_bytes(substream);
    if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
        prtd->pos = 0;

    snd_pcm_period_elapsed(substream);
}

static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
    struct dma_chan *chan = prtd->dma_chan;
    struct dma_async_tx_descriptor *desc;
    enum dma_transfer_direction direction;
    unsigned long flags = DMA_CTRL_ACK;

    direction = snd_pcm_substream_to_dma_direction(substream);

    if (!substream->runtime->no_period_wakeup)
        flags |= DMA_PREP_INTERRUPT;

    prtd->pos = 0;
    desc = dmaengine_prep_dma_cyclic(chan,
        substream->runtime->dma_addr,
        snd_pcm_lib_buffer_bytes(substream),
        snd_pcm_lib_period_bytes(substream), direction, flags);

    if (!desc)
        return -ENOMEM;

    desc->callback = dmaengine_pcm_dma_complete;
    desc->callback_param = substream;
    prtd->cookie = dmaengine_submit(desc);

    return 0;
}

int snd_dmaengine_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
    int ret;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        ret = dmaengine_pcm_prepare_and_submit(substream);
        if (ret)
            return ret;
        dma_async_issue_pending(prtd->dma_chan);
        break;
    case SNDRV_PCM_TRIGGER_RESUME:
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        dmaengine_resume(prtd->dma_chan);
        break;
    case SNDRV_PCM_TRIGGER_SUSPEND:
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        dmaengine_pause(prtd->dma_chan);
        break;
    case SNDRV_PCM_TRIGGER_STOP:
        dmaengine_terminate_all(prtd->dma_chan);
        break;
    default:
        return -EINVAL;
    }

    return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_trigger);

snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream *substream)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
    return bytes_to_frames(substream->runtime, prtd->pos);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer_no_residue);

snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
    struct dma_tx_state state;
    enum dma_status status;
    unsigned int buf_size;
    unsigned int pos = 0;

    status = dmaengine_tx_status(prtd->dma_chan, prtd->cookie, &state);
    if (status == DMA_IN_PROGRESS || status == DMA_PAUSED) {
        buf_size = snd_pcm_lib_buffer_bytes(substream);
        if (state.residue > 0 && state.residue <= buf_size)
            pos = buf_size - state.residue;
    }

    return bytes_to_frames(substream->runtime, pos);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);

static int dmaengine_pcm_request_channel(struct dmaengine_pcm_runtime_data *prtd,
    dma_filter_fn filter_fn, void *filter_data)
{
    dma_cap_mask_t mask;

    dma_cap_zero(mask);
    dma_cap_set(DMA_SLAVE, mask);
    dma_cap_set(DMA_CYCLIC, mask);
    prtd->dma_chan = dma_request_channel(mask, filter_fn, filter_data);

    if (!prtd->dma_chan)
        return -ENXIO;

    return 0;
}

int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
    dma_filter_fn filter_fn, void *filter_data)
{
    struct dmaengine_pcm_runtime_data *prtd;
    int ret;

    ret = snd_pcm_hw_constraint_integer(substream->runtime,
                        SNDRV_PCM_HW_PARAM_PERIODS);
    if (ret < 0)
        return ret;

    prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
    if (!prtd)
        return -ENOMEM;

    ret = dmaengine_pcm_request_channel(prtd, filter_fn, filter_data);
    if (ret < 0) {
        kfree(prtd);
        return ret;
    }

    substream->runtime->private_data = prtd;

    return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);

int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream)
{
    struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);

    dma_release_channel(prtd->dma_chan);
    kfree(prtd);

    return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_close);